Chapter 44-17The CMOS sensor outputs are necessary even for the following reasons even when the density of the original is uniform:(1) Variation in sensitivity among CMOS sensor pixels(2) Variation in light intensity of rod lens arrayThe machine performs shading correction to even out the CMOS sensor output.There are two types of shading correction: shading adjustment performed in the Service mode and shading correction performed for each job.4.3.6.6 Shading Adjustment 0017-2641iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018iThe machine measures the density of the standard white plate, and stores the measured density data. It then processes the stored data to use it as the target value forshading correction.4.3.6.7 Shading Correction 0017-2642iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018iThe machine performs shading correction for each scan. It measures the density of the standard white plate, and compares the measured value with the target valuestored in the shading correction circuit to use the difference between the two as the shading correction value. The machine uses this shading correction value tocorrect the variation among CMOS sensor pixels when scanning the original, thus evening out the image density level.F-4-32CMOSsensoroutputOriginal densityStandard white plateCharacteristicsbefore correctionTargetvalueMeasurementvalueCharacteristicsafter correctionWhite
